This invention relates generally to brake holding apparatus adapted for use in an automotive vehicle. More particularly, it relates to such apparatus for use between a master cylinder and the brake cylinders to provide anti-roll, anti-creep and anti-theft functions.
U.S. Pat. No. 2,522,835 issued to R. L. Mayrath on Sept. 19, 1950 discloses a brake holding device which uses a solenoid actuated valve and a check valve to trap brake fluid in the brake cylinders. However, the trapped fluid develops a force which opposes the force applied by the solenoid. Thus the braking pressure is limited by solenoid capacity. Further, the Mayrath device is vacuum controlled, and thus subject to variables in engine and load characteristics.
There remains a need in the art to improve upon brake holding devices of the Mayrath type in order to increase the available braking pressure, operate independently of manifold pressure, and at the same time reduce the force required to actuate the holding device, thus improving operating efficiency.